Sound source



Dec. 28, 1965 L. R. PADBERG, JR 3,226,671

SOUND SOURCE Filed April 5, 1962 s Sheets-Sheet 1 FLUID 7 POWER SUPPLY1/3 SOUND SOURCE ELECTRIC POWER SUPPLY INVEN TOR. LOU/S n. P408556; JE.

Dec. 28, 1965 R. PADBERG, JR

SOUND SOURCE 3 Sheets-Sheet 2 Filed April 3, 1962 INVENTOR. LOU/5 R. PA055/76, .12

ATTORNEYS Dec. 28, 1965 L. R. PADBERG, JR

SOUND SOURCE 3 Sheets-Sheet 5 Filed April 5, 1962 ATTORNEYS UnitedStates v Patent 3,226,671 SOUND SOURCE Louis R.'Padberg, Jr., 22'RinconVista Road, Santa Barbara, Calif. Filed Apr. 3, 1962, Ser. No. 184,86312 Claims. (Cl. 3405) (Granted under Title 35, US. Code (1952), sec.266) The invention'described herein may be manufactured and-.usedby orfor the Government of the United States of America for governmentalpurposes without thepayment of any royalties thereon or therefor.

The present invention relates in general to sound sources and inparticular is a high intensity Wolf Whistle type sound generatorespecially suited for broadcasting acoustical energy throughout asubaqueous medium during sonar operations.

In' the past, numerous sound sources which were adequate for manypurposes have been developed. These soundsou-rces, for example, havebeen used for musical, communication, echo-ranging, and otherpurposes,but, to date, a simple sonar sound source having the intensity andpowerrequired for optimum efdciency in sonar operations has not beendeveloped to the complete satisfaction of those working in the field.However, the device of this invention does constitute an overallimprovement over many of the sound sources employed inthesonar field inthat it is exceedingly simple to construct, maintain, and operate and,furthermore, it produces sonic energy of an improved nature, thequalilative results of which .are superior to those of the prior art formany operational purposes. It particularly overcomes some of thedeficiencies of the prior art because of its improved power output perpower inputratio and the unique type of-sonicenergy produced.

It is, therefore, an object of this invention to provide an improvedacoustical energy generator.

' Another objectof this invention is to provide an improved sonar soundsource.

Still another object of this invention is to provide a method and meansof producing a unique highintensity sound.

A further object of this invention is to provide animproved method andmeans of broadcasting acoustical energy-of predetermined fluctuatingfrequencies within an aqueous medium.

.Another object of this invention is to provide a method and means ofusing mechanical feedback to generate inphase sound waves.

A further object of this invention is to provide an improved. method andmeans for producing a highpowerhigh intensitysonic signal from a pair.of interacting resonated devices.

Another object of this invention is to provide a rugged sound sourcethat may be easily and economicallymanufactured and maintained.

Other objects and many of the. attendantadvantages of thisinvention willbe readily appreciated as the. same becomes .better, understood byreference to thefollowing detailed description when considered inconjunction with the accompanying drawings in which like referencenumerals designate like parts throughout the .figures thereof andwherein:

FIG. 1 is a'block diagram representation of the subject inventionconnected to its associated electrical and fluid power supply sources;

FIG..2 pictorially depicts anexemplary preferred embodiment of thesubject invention as. having a tensionedband type reed 'for generatingthe acoustical excitation r y;

FIG. 3 pictorially shows anotherpreferred embodiment of the subjectinvention as having a pair of con- "ice tiguously disposed flutter-typereeds for generating the acoustical excitation energy; and

FIG. 4'is a side view-0f the embodiment-of-FIGyB with some of theelements thereof illustrated in crosssection and some illustrated inpictorialform.

Referring now-to FIG. 1, a system incorporating the sound sourceof thisinvention is shown as'having a fluid power supply '11 and an electricpower supply .12 which are connected as inputs to a sound. source 13 forsupplying the fluid power'and electrical power thereto, respectively.

FIG. 2 depicts one of the prefer-red embodiments of sound source 13disclosed herein as having a metallic tubular resonant chamber 14 havingan openend 15 .and a flanged end 16 with an end plate 17 attached.thereto as by bolts 18 or by any other well-known conventional manner.Passing through an aperture in end plate 1-7 is a hollow tube 19 capableof having any predetermined fluid such as, for example, air or waterflowtherethrough. Attached to one end of said tube 19-is a fitting 20adaptedto be connected to a hoseor conduit means (not shown in FIG. 2) which,in turn, is coupled to the aforesaid fluid power supply 11. On the otherend of said tube 19 is a nozzle 21 that hasan orifice 22 that issmallerthan the inside diameter of tube 19.

Diametrically opposed at the end of chamber 14 which is open, there ismounted a pair of reed-supports, each of which consists of a crossbar 24having a slot 25 which is open to one of theside edges thereof and apair of shafts 26 and '27 attached at each extremity of said crossbar,in a direction normal to the longitudinal axis thereof. Said shaftsrespectively extend through a pair of rubber grommets Y28 and 29disposed ina complementary pair of holes located inthe wall of resonantchamber 14. At the other end of shafts. 26 and 27 is mounted anothercrossbar 30 having a hole in the center thereofcontaining screw threads.Anadjustrnent screw 31 is threaded in the screw threads of crossbar 30.and is ofsuch length as to contact the outside of the resonantchamber-wall. Disposed within the slot is a thin metallic blade orreed32 having end stops o-r beads 33 attached tothe outer extremitiesthereof for contact with the outer face of each of theaforesaid-crossbars24. Although the aforementioned reed 32 is preferablydisclosed herein as being a spring steelreed, itshould be understoodthat anyappropriate vibrating body or element may be substitutedtherefor without violating the spirit and .scope of this inventionbecause so doing would obviously be within the purview of the skilledartisan after:he had'the. benefit of teachings herein presented.

The aforementioned hollow tube 19 extends through a hole in endplate 17in such manner that it is securely mounted therein. Preferably, however,the securingof said tube 19 shoulde be accomplished by means of apacking gland 34 which permits tube 19.to be .slidably moved therein inorder to effect any desired tube length within resonant chamber 14.

Resonant chamber 14 and its associated apparatus is preferably mountedon a base plate 35 having one or more supports 36.

.At an adjustable distance from the open end '15 of resonant chamber 14avariable deflector plate assembly is positioned. This assenibly includesa deflector plate 37 mountedon a shaft 38 by meansofscrews 39-.oranyother suitable conventional connecting means. Shaft 38 is disposedwithin bearing holes 40 of bracketsil in such manner that both saidshaftand deflector plate may be rotated or not as desired. 'Brackets41,of course, are so disposedas to have deflector plate 37 interposedtherebetween and in the path of any acoustical energy emanating-from theopen end of resonant chamber 14. Brackets 41 are also integrally'mountedon an invertedU-shaped bracket 42 having flanged ends 43 which act asfeet that rest upon the upper surface of base plate 35. Flanged end 43each have an elongated slot 44 disposed therein in such manner that theentire deflector plate assembly may be moved nearer to the open end ofresonant chamber 14 are further away therefrom as necessary to achieveany preferred operational objective. An adjustment set screw 45 is usedto hold the flanged end of the aforesaid deflector plate assembly inrigid contact with base plate 35, thereby maintaining a given distancebetween reed 32 and deflector plate 37. Disposed on one of the aforesaidflanges 41, preferably on the outside surface thereof, is a waterproofreversible variable speed electric motor 46 which is also attached toone end of shaft 38 for rotation thereof. At the other end of shaft 38is a knob 47 attached thereto for manual rotation of deflector plate 37if desired.

Referring now to FIGS. 3 and 4, there is shown another preferredembodiment of sound source 13 which is substantially identical to thesound source disclosed in FIG. 2 except for the vibrating reed assembly.Therefore, all of the elements except those of the vibrating reedassembly are referenced by reference numerals which are the same asthose used to designate their respective operable elements of the soundsource illustrated in FIG. 2.

As is shown in FIGS. 3 and 4, the vibrating reed assembly and itsassociated support structure is mounted directly on the nozzle end offluid supply tube 19. Actually, said reed assembly is mounted on saidnozzle 21 in a snug fit arrangement effected by a split plate 48 with athickness that is slightly less than that of the outside diameter ofnozzle 21 at its thickest location. At the split of plate 48 there isdisposed a pair of semicircular apertures which form a circular aperturewhen the ends thereof are placed together. Said aperture, of course, areso designed as to snugly fit about the outside surface of nozzle 21without distorting the structural configuration thereof. Due to theabutment of split ends of said split plate 48, the upper and lowersurface thereof remains a substantially continuous surface as far as theassociated parts are concerned. Thus, a pair of reeds may be supportedby said surface without being adversely affected by the slit. Thissupport is achieved by means of upper and lower plates and 51 which arebolted by means of bolts 52 to the aforesaid split plates 48. Thus,nozzle 21 and a pair of vibrational reeds 53 and 54 are sandwiched andclamped therebetween in a pressed fit assembly.

Although this particular arrangement for securely mounting thevibrational reed assembly to nozzle 21 is one of the preferred typesdisclosed herein. Any suitable arrangement which holds said reeds intheir respective illustrated position would be satisfactory to achievethe operational objectives of this invention.

At the outer extremities of split plate 48 there are a pair of cars 55each of which contain a threaded hole for having adjustable screw bolts56 screwed therein. Spatially disposed from the orifice of nozzle 21 isa pair of bars 57 and 58 which are used to clamp reeds 53 and 54together in such manner that there is room for them to vibrate againsteach other and said bars. Bars 57 and 58 are held together by means ofscrews 59 which are adjustable in order to allow adjustments of theproper space between reeds 53 and 54 from effecting any predetermineddesired flutter frequency thereof. Bolts 56 extend through matingapertures of bars 57 and 58 in such manner that said bars are rigidlydisposed and properly held together at some preferred distance from theend of nozzle 21 by screws 59 in order to effect optimum fluttercharacteristics of said reeds during any given operationalcircumstances.

Briefly, the principle of operation of the subject invention is asfollows:

Under certain circumstances, a sympathetic resonance may occur between atone generating means such as a vibrating string or reed and the soundbox of a musical instrument. The resulting effect is usually undesirabledue to its high intensity, unmelodious, Screech-like sound which causesit to be considered unpleasant to the human ear. Because such sounds arenot intentionally made by the musician, and inasmuch as they ordinarilyare beyond the control thereof, they have been defined in physicstextbooks as a wolf-tone.

Such a tone, although undesirable in the musical field, is useful incertain acoustical operation such as, for example, in sonar operations,because it may be elficiently produced and employed to move various andsundry media subject to presure wave differentials such as sea water,fresh Water, or other aqueous mediums. Hence, the unique structureconstituting this invention has been constructed for the purpose ofintentionally generating such wolf-tone sounds at predetermined varying,fluctuating, or constant frequenices as desired. 1

In this case, the vibrating member which originally generates thefrequency desired is the metallic reed element or elements.

In the embodiment of FIG. 2, this is depicted as a single metallic bladethat is stretched with a predetermined tension across the insidediameter of the resonant chamber. Obviously, due to the disclosed reedsupport members, the tension thereof may be manually adjusted by screws31 to obtain the tautness and, hence, the tonal pitch desired. The reedis energized or vibrated by passing air, water, or any other appropriatefluid over it from a properly positioned nozzle. Of course, the power ofenergization of said reed will vary with the pressure and velocity ofthe fluid jet flowing from the orifice of the nozzle and the manner inwhich it strikes the reed. However, since these parameters are alladjustable, it would be obvious for the artisan to make the properdesign selection thereof which would suit any size and type sound sourceof the disclosed types being used, as well as the circumstances underwhich they are to operate.

Resonant chamber 14 is sympathetically excited by the vibrating memberand when the two are in resonance, a substantial sound level will beattained. Relative positioning of said vibrating member and resonantchamber, of course, should be such as will produce optimum powerefiiciency due to maximum acoustical transfer and interactiontherebetween. Accordingly, the positioning thereof should be adjustableand regulated in accordance with the inherent characteristics of eachthat are involved.

At an adjustable distance from the aforementioned vibratingreed-resonant chamber assembly, the rotatable deflector plate ispositioned. At a certain critical angle thereof, the sound emanatingfrom the open end of the resonant chamber will be reflected asmechanical or acuostical feedback into the resonant chamber in phasethere- With. The result is a greatly increased acoustical output energylevel.

Depending on operational circumstances encountered, said deflector maybe positioned manually and constantly secured to produce the frequencypreferred. Or, in the alternative, it may be rotated at any preferredspeed and direction by properly controlling the reversible,variablespeed motor attached to one end of the shaft upon which it ismounted. So doing causes a fluctuating tone to be generated which isdesirable for some applications.

The embodiment of the subject invention illustrated in FIGS. 3 and 4work in essentially the same manner as the embodiment of FIG. 2. Ahigh-speed jet of fluid from the nozzle energizes a pair of contiguouslydisposed reeds instead of a single reed to initiate the generation ofsonic energy. Otherwise, the operations are the same.

In this disclosure, only metallic spring blade type reeds are shown asthe vibrating sound generators. But, it should be understood that manytypes of vibrating means such as, for instance, vibrating rods, strings,bars, balls, etc., may be employed without violating the scope andspirit of this invention, since so doing would obviously be well withinthe purview of one skilled in the art after he had the benefit of theteachings herein presented.

Obviously, many modifications and variations of the present inventionare possible in the light of the above teachings. It is, therefore, tobe understood, that within the scope of the appended claims, theinvention may be practiced other than as specifically described.

What is claimed is:

1. A sound source comprising in combination, a resonant chamber, meansdisposed within said resonant chamber for generating acoustical energytherein for effecting vibratory excitation thereof, and means disposedexternal of said' resonant chamber in the path of said generatedacoustical energy for reflecting same back thereto in phase with thevibration thereof.

2. The device of claim 1 wherein said resonant cham her is a hollowcylinder with a closed end and an open end.

3. The device of claim 1 wherein said means disposed within saidresonant chamber for generating acoustical energy therein for effectingvibratory excitation thereof comprises a tube adapted for transporting apressurized fluid therethrough, nozzle means mounted on the end of saidtube for increasing the velocity of said fluid as same is ejectedtherefrom, a pair of adjustable supports each of which is mounted atdiametrically opposed positions on the aforesaid resonant chamber, and avibratable reed suspended between said pair of supports in such manneras to be adjusted in tension and frequency of vibration, said reed beingdisposed in the path of the fluid ejected from said nozzle.

4. The device of claim 1 wherein said means disposed within saidresonant chamber for generating acoustical energy therein for effectingvibratory excitation thereof comprises, a hollow tube adapted fortransporting a pressurized fluid therethrough, nozzle means mounted onthe end of said hollow tube for increasing the velocity of said fluid assame is ejected therefrom, a pair of vibratory reeds contiguouslydisposed with each at a position spaced from the end of said nozzle andin the path of the fluid ejected therefrom, said reeds being curved insuch manner as to extend from said fluid path to a position on oppositesides of said nozzle respectively, and means interconnecting said nozzleand said reeds for supporting those portions thereof extending on theopposite sides of said nozzle in a substantially fixed relative positiontherewith.

5. The device of claim 4 further characterized by a first bar contactingone of said pair of reeds opposite the side thereof disposed in the pathof said ejected fluid, a second bar contacting the other of said pair ofreeds opposite the side thereof disposed in the path of said ejectedfluid, means interconnecting each of said pair of bars for maintainingsame in substantially predetermined relative positions, and meansconnected between the aforesaid reed supporting means and said pair ofbars for spatially maintaining said bars a predetermined distance fromsaid nozzle.

6. A wolf whistle sound source comprising in combination, a. hollowcylindrical resonant chamber, vibrating means disposed adjacent to oneend of said hollow cylindrical resonant chamber for generating sonicenergy, means connected to said vibrating means for adjusting thefrequency thereof within predetermined limits, and a rotatable planardisc disposed external of said hollow cylindrical resonant chamber inthe path of said sonic energy for reflecting a portion of said energyinto said chamber.

7. The device of claim 6 further characterized by means connected tosaid rotatable sonic energy reflecting means for manually rotating sameto any predetermined fixed position.

8. The device of claim 6 further characterized by means eifectivelyconnected to said rotatable sonic energy reflecting means for adjustablypositioning same at any predetermined distance from the aforesaid hollowcylindrical resonant chamber.

9. The device of claim 6 further characterized by motor meanseflectively connected to said rotatable sonic energy reflecting meansfor rotating same at any predetermined speed.

10. A sound source comprising in combination, a resonant chamber,vibration means disposed adjacent to one end of said resonant chamber,means spatially disposed from said vibration means for energizing samein such manner as to effect generation of predetermined frequencyacoustical energy, means connected to said vibrating means for adjustingthe frequency thereof within predetermined limits, and rotatable meansspatially disposed from said resonant chamber for reflecting saidacoustical energy back into said chamber.

11. A method of producing a wolf tone comprising the steps of vibratinga reed for generating acoustical energy, resonating a chamber with theacoustical energy generated by said vibrating reed, and reflecting aportion of said acoustical energy back into said chamber in phase withthe resonance frequency thereof after it has emanated therefrom.

12. A method of broadcasting sonar signals within an aqueous mediumcomprising the combined steps of energizing a chamber at its resonancefrequency with predetermined acoustical energy, reflecting a portion ofsaid acoustical energy back into said chamber in a predeterminedvariable phase relationship with the resonan ce frequency thereof afterit has emanated therefrom, and submerging said chamber within theaforesaid aqueous medium while said portion of acoustical energy isbeing reflected back thereinto.

References Cited by the Examiner UNITED STATES PATENTS 1,113,400 10/1914Baumgartner 116-137 1,540,023 6/1925 Kollinek 116137 2,462,862 3/ 1949Guthner 116147 OTHER REFERENCES L. R. Padger, Jr., Novel Sound Sources.NEL Report 990 U.S. Navy Electronics Las., San Diego, California,October 17, 1960, pages 60-61.

CHESTER L. JUSTUS, Primary Examiner.

I. N. MILLS, G. M, FISHER, Assistant Examiners.

1. SOUND SOURCE COMPRISING IN COMBINATION, A RESONANT CHAMBER, MEANSDISPOSED WITHIN SAID RESONANT CHAMBER FOR GENERATING ASCOUSTICAL ENERGYTHEREIN FOR EFFECTING VIBRATORY EXCITATION THEREOF, AND MEANS DISPOSEDEXTERNAL OF SAID RESONANT CHAMBER IN THE PATH OF SID GENERATEDACOUSTICAL ENERGY FOR REFLECTING SAME BACK THERETO IN PHASE WITH THEVIBRATION THEREOF.